Answer:
C: Sodium chloride
Explanation:
Common salt is gotten when sodium atoms reacts with chlorine atoms in an exothermic reaction to form an ionic substance known as sodium chloride with the chemical formula NaCl.
Equation is;
2Na + Cl2 = 2NaCl
Looking at the options, the correct one is Sodium chloride.
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Answer : The
for this reaction is, -88780 J/mole.
Solution :
The balanced cell reaction will be,

Here, magnesium (Cu) undergoes oxidation by loss of electrons, thus act as anode. silver (Ag) undergoes reduction by gain of electrons and thus act as cathode.
The half oxidation-reduction reaction will be :
Oxidation : 
Reduction : 
Now we have to calculate the Gibbs free energy.
Formula used :

where,
= Gibbs free energy = ?
n = number of electrons to balance the reaction = 2
F = Faraday constant = 96500 C/mole
= standard e.m.f of cell = 0.46 V
Now put all the given values in this formula, we get the Gibbs free energy.

Therefore, the
for this reaction is, -88780 J/mole.
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